LONDON (AP) — The so-called "Big 4" who have won 35 of 37 of the past Grand Slam singles titles — Novak Djokovic, Rafael Nadal, Andy Murray and Roger Federer — are all around for the second week at Wimbledon, joined by the new major winner on the block, Australian Open champion Stan Wawrinka.

The same can't be said on the women's side, where top-seeded and five-time champion Serena Williams won't see any action at the All England Club in Week 2 except in doubles with her sister Venus, another five-time Wimbledon winner who is also out of singles.

With Serena out and second-seeded Li Na also a third-round loser, it marks the first time in the Open era that the top two women's seeds haven't advanced to Wimbledon's fourth round.

Williams, who has 17 Grand Slam singles titles, hadn't been knocked out of Wimbledon so soon since 2005, but has departed before the quarterfinals at four of the past five majors.

WTA founder Billie Jean King, winner of eight Grand Slam singles titles in the Open era, says she recalls going through a similar streak in her career.

"Most definitely," King said Sunday near Wimbledon when announcing Singapore as the new site of the WTA season-ending championships in October.

"Everybody does. But I think there might be some underlying things happening to her, some things off the court, that are affecting her. I'm sure she will work them out."

On a sunny but blustery middle Sunday — traditionally an off-day at Wimbledon — most of the players remaining in the singles draw held sessions at the nearby Aorangi Park practice courts.

Federer and Murray were there at the same time, although due to rain delays on Friday, Federer, like Nadal, won't play his fourth-round match until Tuesday.

Federer says he's amazed as anyone about the Big 4's ability to maintain such a stellar record in Grand Slam tournaments.

"I came through the ranks where it was normal for top guys to have a bad Slam, have maybe two bad Slams from time to time, but it barely happens anymore," Federer said. "It's like such a shock when it does.

"I think I've been surprised how consistent I've been personally, but even more so by everybody else who is just like normal to get to quarters, get to semis. Because I know how small the margins are."

Djokovic's chances of advancing might rest with his sore arm. He had an afternoon training session Sunday to test his left arm and shoulder he injured in a nasty fall on Friday in his Centre Court win over France's Gilles Simon.

Djokovic lunged for a shot behind the baseline, tumbled on the grass and rolled over twice, his racket flying from his hand. He thought he had dislocated his shoulder, but from what Djokovic says, it looked a lot worse than it was.

"Luckily there is nothing damaged," he said. "I just came from the doctor's office, ultrasound. I'm quite confident that it will not affect my physical state or regimen or daily routine. I think it's going to be fine."

Djokovic will play the third match on Centre Court on Monday against 14th-seeded Jo-Wilfried Tsonga.

Alize Cornet, who scored the biggest upset of the tournament when she beat Serena Williams on Saturday, opens Monday's play on Centre against Canadian Eugenie Bouchard, who is the only woman to advance to the semifinals of both Grand Slam tournaments this year.

In third-round matches carried over due to Saturday's rain suspensions, Wawrinka is up against Denis Istomin to start play on Court 2 while Feliciano Lopez plays American John Isner on Court 3.

The only other third-round men's match to be completed is nearly there — Kei Nishikori of Japan and Italy's Simone Bolelli are 3-3 in the fifth set, with the winner to play Canadian Milos Raonic on Tuesday.

British tabloids will no doubt have fun with the back-to-back "love" matches on Court 1 on Monday.

Not to miss an opportunity, a gambling agency, calling Dimitrov and Sharapova "the most glamorous couple in tennis (since Connors and Evert in 1974)" are offering odds of 50 to 1 that the pair will win their respective singles titles this year.

And, oh, 250 to 1 that they'll announce their engagement before the end of the Wimbledon Champions Ball.